Kelvin Harrison Jr. in “Chevalier.” Larry Horricks/Searchlight Pictures

Largely erased from classical music history because he was biracial, the 18th-century French Caribbean violinist and composer Joseph Bologne wrote concertos, sonatas and symphonies. But “Chevalier,” a highly fictionalized account of Bologne’s life, understandably concentrates on his opera “Ernestine.” The movie itself has the virtues and vices of opera: It’s grand, sweeping and lavishly appointed, but also bombastic and contrived.

Director Stephen Williams and screenwriter Stefani Robinson present Bologne’s life largely as a series of contests. In the opening sequence, a cocky young Bologne (Kelvin Harrison Jr.) challenges the better-known Wolfgang Amadeus Mozart (Joseph Prowen) to a violin duel. (In reality, Bologne was a decade older than Mozart, who surely wouldn’t have responded to such a rival’s crowd-pleasing stunt with an unprintable Anglo-Saxon vulgarity.)

Later, the story flashes back to a fencing match in which Bologne faces an outspoken racist, as Marie Antoinette (Lucy Boynton) watches. He triumphs, and the queen anoints him Chevalier de Saint-Georges, a name derived from his white father’s plantation in Guadeloupe. His mother (Ronke Adekoluejo) was enslaved but may have been treated somewhat better by Bologne’s father than “Chevalier” supposes.

The bulk of the movie concerns Bologne’s campaign to become the new director of the Paris Opera, a quest in which he initially has Marie Antoinette’s support. (Her husband, King Louis XVI, barely registers.) This effort is intertwined with another one: the womanizing composer’s successful pursuit of his leading lady, the delicate but mighty-voiced Marie-Josephine (Samara Weaving). She just happens to be married to the brutish Marquis de Montalembert (Marton Csokas), a stalwart defender of the monarchy.

Kelvin Harrison Jr., left, and Lucy Boynton in “Chevalier.” Larry Horricks/Searchlight Pictures

That last detail matters because the guillotine is about to be rolled into the Place de la Révolution. Bologne cultivates the queen and the nobility but also encourages an aristocratic friend (Alex Fitzalan) who supports the imminent uprising. At one point, soft-spoken Marie-Josephine follows the two pals to a clandestine political conclave where she delivers an impromptu speech in favor of women’s liberation. It’s stirring, but about as believable as the street fair in a Black neighborhood where Bologne joins a drum circle in playing what sounds like contemporary Afro-pop.

As anti-royalist sentiment burgeons, Bologne stages a benefit concert for the insurrection and faces a personal crisis. This section of the movie plays like the last act of “Les Misérables” with a dusting of Black history. But rather than pop-operatic Broadway arias, “Chevalier” mixes Kris Bower’s neoclassical score with snippets of Bologne’s partly lost compositions, as reconstructed and extrapolated by Michael Abels, who’s written the music for three Jordan Peele films.

Bologne, whose impressive military career is among the many chapters of his biography left out of the movie, briefly commanded a unit of the French Revolutionary Army. As played by Harrison – one of the few Americans in a cast heavy on Britons, Australians and New Zealanders – Bologne does appear to be the sort of leader who could inspire soldiers in battle, or musicians in an orchestral performance. His confidence and dynamism are crucial to “Chevalier’s” winning spirit.

If Harrison doesn’t fully convey the complexity of Bologne’s situation, that’s the responsibility of the film as much as his performance. One snag is that the movie shares its hero’s mixed feelings about the gilded lives of France’s 18th-century ruling class. Jess Hall’s camera spins rapturously through Karen Murphy’s luxurious interiors, lovingly beholding Oliver Garcia’s opulent costumes. On some level, “Chevalier” understands that the reign of Louis XVI and Marie Antoinette was the bad old days. Yet it just can’t help but make them look really good.